Category Archives: Portable Radio

Getting the Grundig G6 out of a sticky situation

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This has been a busy week, but Wednesday evening I took a few minutes to finally remove the sticky residue on my Grundig G6.

In case you’re not familiar, back in the day (roughly 2009 to 2013) Eton/Grundig covered a number of their radios models with a rubberized coating that unfortunately breaks down over time and becomes tacky or sticky to the touch. The Grundig G6 was one of those radios.

If you’ve been an SWLing Post reader for long, you’ve also no doubt read our numerous posts about cleaning off this mess. There are a number of solutions, but it seems the most positive long-term results by employing a de-greasing product called Purple Power (click here to read archived posts). Indeed, it’s the solution Eton Corporation recommends and the one I used to clean my Eton E1 XM.

Pre-cleaning, the G6 was incredibly sticky. It’s hard to see in the photos, but it was so sticky, it was challenging to remove it from its OEM pouch where it had been stored.

The Purple Power solution is effective, though. It requires only a few minutes to clean off the residue, then another few minutes to do a final polishing (I use a simple window cleaning solution).

The results are so impressive.

When I pulled the G6 from its pouch before cleaning, the back stand fell off. I believe it actually stuck to the inside of the pouch.

I’ll likely follow in Troy’s footsteps and eventually replace it with a 3D printed one. I’m not in a hurry at this point, though, as I’ve so many other things on my plate at present.

It’s so great to enjoy the G6 once again. It is a gem of a compact portable. One thing that surprised me? I forgot how fluidly the tuning works with no muting between frequency changes and how quickly (immediately) it switches into SSB mode. In the day an age of DSP portables, we’ve forgotten that these legacy receivers are actually better at both of these tasks.

Next up is my Grundig G3 which is quite sticky. I need to pull it from its storage bin.

Have you rescued a sticky radio recently? Please comment!

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Radio life after death

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A guest post by Troy Riedel:

This is a sad story.  Well, it’s sad for me.  But hopefully my sad story will yield “radio life” for somebody else and that life will bring them joy.

I’ve been an SWL’er since the early-90s.  Due to the decline of international broadcasters, “collecting” has become just as – if not more – important to me than listening.  I’ve always been fond of the Sony ICF-SW100 pocket radio.  I often read here on this blog about Thomas’ affection for it.  To make my dream a reality, on 19 November 2017 I found the perfect SW100 (with the leather case) and I purchased it.  It did not disappoint!  That radio has to be the most sensitive radio for its size out there.  No, correction – that little baby has held its own against any other portable shortwave radio (of any size) that I own (I have 17 or 18, incl. this SW100).  That’s quite amazing for a true pocket radio.

But please allow me go back to the beginning of my story.  Once I acquired the ICF-SW100, I assembled a “kit” … piece-by-piece (remember, I’m a collector).

I surmised that the SW100 would fit into the Sony ICF-SW1 case – and I was correct (sans the SW100’s leather case).  The SW1 case was one of my first purchases for my SW100 as I wanted something rugged to protect it.

The Sony AN-1 antenna works great with the SW100, and that was part of my kit.  Of course, I also wanted the OEM Sony Compact Reel Antenna.  “Check” – found one on eBay!  The OEM AC adapter? Yes, “check” that one off the list.  A photocopy of the OEM manual would not do – I found an original on eBay and “check”, that was added to the kit.

I already owned a Sony AN-LP1 (active) antenna.  That would not fit into the case, so I added a TG34 active antenna that I already owned (that’s a Degen 31MS clone).  Why?  I gotta have a ready passive antenna in my kit.

Wait, who wants a 30+ year old OEM set of earbuds?  Exactly, neither do I.  This is the only thing I did not want to be OEM!  I bought a new pair of Sony earbuds (off Amazon) to throw into the kit.  Other than the TG34, everything in the kit had to be Sony.  In the end, this handy little case was my Eutopia – it had everything I needed in its own “shortwave bugout kit”.

Of all of the radios in my shortwave arsenal, this was by far my favorite.  Hobbies should bring us joy.  So even if there weren’t many broadcasters to listen to, this little pocket radio never failed to bring me joy.

The last time I really used this radio was June-August 2020.  My newborn grandson was in the NICU far from my son’s home.  I “deployed” (with my SW100 bugout kit & 5th wheel camper) to my son’s very rural & very remote farm (275-miles from my home).  I was there to tend the farm, solo, for that period of time while my son and his family could be with my grandson at a specialty hospital some 350-miles away.  During this stressful & physically demanding time – tending to more farm animals than I care to mention and rustling bulls that escaped from the pasture – my SW100 was the only friend that I had.  It provided many, many hours of enjoyment.  Literally, other than a neighbor about ¾ of a mile up the road my ICF-SW100 and I were alone (not including the 50+ animals I tended to) from June through August.

Fast-forward to the present: last weekend I reached for my kit and I removed the my SW100.  I turned it on and there was no power.  Not surprising but actually very unusual as my NiMH Eneloop batteries typically last for a year or more inside my radios in “storage”.  I reached for the battery compartment, I felt an anomaly on the backside of the case and imagine my horror seeing this as I turned it over!

Surprisingly, there is zero damage to the Eneloop batteries (they did not leak).  I can no longer power the radio via ANY batteries, but amazingly the radio seems to operate at full capacity via AC Adapter.  Whatever happened inside the radio, it still seems to operate (though admittedly I haven’t taken it through all of its usual paces).

Unfortunately, a pocket radio that only operates via AC power does not suit me.  There is a better option: my loss may be someone else’s gain?  I am sending the radio and the necessary components to Thomas’s friend Vlado for a full autopsy (Vlado emailed that he has worked on these radios for years and has “never” seen this issue before).  After the autopsy, my radio will become an organ donor.  The remaining healthy components of this radio – and there are many – will be used for repairing other SW100s (singular or plural).

Strangely, I cannot detect any other “trauma” to the radio other than that one melted corner.  The battery compartment *seems* undamaged though I refuse to open the case as I do not want to accidentally damage the radio’s healthy components (I’ll let the professional “coroner” do that).  I am looking forward to the coroner’s report because I need to know what the heck happened to my baby?!

In closing, though we’ve only had a 3-year plus relationship I can honestly say this amazing little pocket radio had become a great friend.  I’m sure it’s grief, but I am considering liquidating the remainder of my radio & antenna collection – my heart just isn’t “in” to SWL at the moment.  And the timing of this is just awful for me: I’m having surgery Tuesday for an injury I incurred eight months ago while tending my son’s farm.  I had big plans that my SW100 and I would pass the time while I convalesce.  But alas, my buddy will be headed to radio heaven as an organ donor.  May others benefit from my loss.

Guest Post by Troy Riedel

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Is AM synchronous detection a crucial portable radio feature?

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Many thanks to SWLing Post contributor, Mike, who writes with the following question:

How important is AM Sync for a portable radio? Is it essential or a deal breaker?

That’s a great question, Mike, and one I don’t think I’ve directly addressed it here on the SWLing Post oddly enough.

Synchronous detection is actually a fairly deep topic to explore–and everyone has their own opinion–but I get the impression that you’d like a simple answer, so I’ll try to keep this as brief as possible. You might follow the comments section of this post as I’m sure some SWLing Post readers will share their thoughts on synchronous detection and how important it is for them.

So what is Synchronous Detection?

I like this concise Wikipedia answer:

In electronics, a synchronous detector is a device that recovers information from a modulated signal by mixing the signal with a replica of the un-modulated carrier. This can be locally generated at the receiver using a phase-locked loop or other techniques. Synchronous detection preserves any phase information originally present in the modulating signal. Synchronous detection is a necessary component of any analog color television receiver, where it allows recovery of the phase information that conveys hue. Synchronous detectors are also found in some shortwave radio receivers used for audio signals, where they provide better performance on signals that may be affected by fading. To recover baseband signal the synchronous detection technique is used.

How does synchronous detection help shortwave, mediumwave, and longwave listeners?

As the Wikipedia article notes above, sync detection can help “provide better performance on signals that may be affected by fading.”

In short: a solid synchronous detector can help stabilize an AM signal which then can help with overall signal intelligibility.

In some modern portable radios, at least, this could come at the expense of audio fidelity (see caveat below).

I use sync detection when the bands are rough, noisy, and QSB (fading) is affecting signals.

A good sync detector will help clean-up and stabilize the signal so that you can hear voice information with less listener fatigue. Sync detectors are also great tools for grabbing station IDs when propagation is less stable. If you have a receiver with selectable sideband synchronous detection, it can also be used as a tool for eliminating adjacent signal interference.

Caveat? Sync detectors vary in terms of quality.

The PL-880 has a synchronous detection “hidden” function. I’m sure it’s hidden because it’s so ineffective. The PL-880 is a fantastic portable, but don’t bother using the sync detector.

Many modern DSP portables sport synchronous detection, but they’re not terribly stable and the audio fidelity can take a big hit as well. Poor sync detectors can make audio sound “tinny” and narrow.

If a sync detector isn’t effective a providing a stable lock on a signal, then it’s pretty much useless. Why? If it can’t maintain a stable lock, it’ll produce very unstable shifting audio, often with the occasional heterodyne sound popping in as well. In those cases, it’s better to turn off synchronous detection.

Benchmark legacy tabletop receivers and modern Software Defined Radios (SDRs) typically have solid, effective sync detectors. Indeed, I rarely have the AM synchronous detector disengaged on my WinRadio Excalibur–that particular SDR and application enhance audio fidelity through sync detection.

I find that I use sync detection less with my Airspy HF+ Discovery and SDRplay RSPdx, for example, because the OEM applications natively does a brilliant job managing unstable signals.

In terms of portables, I’ve always considered the sync detector of the Sony ICF-2010, Sony ICF-SW7600GR, and PL-660/PL-680 to be pretty solid. I’m sure readers can suggest even more models.

Is sync detection an essential feature on a portable radio?

Not for me. But I do admit that I value the radios I own that sport a good sync detector.

For some SWLs and DXers, however? It might very well be a deal-breaker if a radio doesn’t have a sync detector, or if its sync detector doesn’t function well.

What do you think?

Is the lack of sync detection a deal-breaker for you? When do you employ sync? Please comment!

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Looking back at 2020: What radios were in heavy rotation at your home and in the field–?

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This morning, I’m looking at the calendar and I see and end in sight for 2020. I think most of us can agree that 2020 will be one for the history books, in large part due to the Covid-19 global pandemic which has had a pretty dramatic affect on many of our lives. It certainly brough my planned travels to a halt. I think many of us are quite happy to show 2020 the door!

As each year comes to a conclusion, I often look back at my radio activities during that year and see how it played out. I especially note the radios I used most heavily throughout the year.

Since I evaluate and test radios, models that are new to the market obviously get a lot of air time. Still, I’m also known to pull radios from the closet and give them some serous air time.

I’m very curious what radios you gave the most air time in 2020?

Here’s my list based on type/application:

Portable shortwave receivers

Since they’re new to the market, both the Tecsun PL-990 (above) and Belka DX (below) got a lot of air time.

I do like both radios and even took the pair on vacation recently even though packing space was very limited. I see the Belka DX getting much more air time in the future because 1.) it’s a performer (golly–just check out 13dka’s review of the Belka DSP) and 2.) it’s incredibly compact. The Belka now lives in my EDC bag, so is with me for impromptu listening and DXing sessions.

A classic solid-state portable that also got a lot of air time this year was the Panasonic RF-B65. Not only is it a performer, but it has a “cool” factor that’s hard to describe. I love it.

Tabletop portables

In a sense, the C.Crane CCradio3 got more play time than any of my radios.  It sits in a corner of our living area where we tune to FM, AM and weather radio–90% of the time, though, it’s either in AUX mode playing audio piped from my SiriusXM receiver, or in Bluetooth mode playing from one of our phones, tables, or computers. In October, the prototype CCRadio Solar took over SiriusXM duty brilliantly. I’m guessing the CCRadio3 has easily logged 1,600 hours of play time this year.

Of course, the Panasonic RF-2200 is one of my all-time favorite vintage solid-state portables, so it got a significant amount of field time.

Software Defined Radios

While at home the WinRadio Excalibur still gets a large portion of my SDR time, both the AirSpy HF+ Discovery and SDRplay RSP DX dominated this space in 2020.

The HF+ Discovery was my choice receiver for portable SDR DXing and the RSPdx when I wanted make wide bandwidth recordings and venture above VHF frequencies.

Home transceivers

Without a doubt the new Mission RGO One 50 watt HF transceiver got the most air time at home and a great deal of field time as well. It’s such a pleasure to use and is a proper performer to boot!

My new-to-me Icom IC-756 Pro, however, has become my always-connected, always-ready-to-pounce home 100W HF transceiver. It now lives above my computer monitor, so within easy reach. Although it’s capable of 100+ watts out, I rarely take it above 10 watts. The 756 Pro has helped me log hundreds of POTA parks and with it, I snagged a “Clean Sweep” and both bonus stations during the annual 13 Colonies event.

Field transceivers

The new Icom IC-705 has become one of my favorite portable transceivers. Not only is it the most full-featured transceiver I’ve ever owned, but it’s also a brillant SWLing broadcast receiver. With built-in audio recording, it’s a fabulous field radio.

Still, the Elecraft KX2 remains my choice field radio for its portability, versatility and incredibly compact size. This year, in particular, I’ve had a blast pairing the KX2 with the super-portable Elecraft AX1 antenna for quick field activations. I’ve posted a few field reports on QRPer.com and also a real-time video of an impromptu POTA activation with this combo:

How about you?

What radios did use use the most this year and why? Did you purchase a new radio this year? Have you ventured into the closet, dusted off a vintage radio and put it on the air?

Please comment!

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Dockside DXing with the super-portable Belka-DX receiver

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I’ve been on the coast of South Carolina enjoying a little R&R with my wonderful family.

We rented a vacation home on a tidal river just south of Charleston, SC and it was just what the doctor ordered. The location was gorgeous, the weather was amazing, and there was very little RF interference outside our home.

The best part? We had full access to a private dock.

I took a few portable radios on vacation (ahem…obviously!) but I so thoroughly enjoyed my time with the Belka-DX.

If you haven’t gathered already, I really appreciate simple radios for field operation and it doesn’t get much more simple than the Belka-DX or Belka-DSP.

The radio is so incredibly compact, durable, and a pleasure to operate–especially if cruising the broadcast bands.

On the dock, I didn’t have a place to easily hang a wire antenna, so I used the supplied telescoping whip antenna. It served me well on a number of listening sessions.

As 13dka pointed out in his brilliant review of the Belka-DSP, the Belka radios are so compact, yet pack so much performance, they smack of a little spy radio! On top of that, the chassis is incredibly durable. I can’t tell you how much I love this. My Belka receiver has been living in my EDC bag in a small zippered pouch.

I barely notice it in my bag–it take up almost no space and weighs so little–but in the back of my mind I know I have a portable DXing machine everywhere I go.

I have no fear of being damaged in my bag, either–the chassis protects it so well.

Since London Shortwave has sorted out how to make spectrum recordings using the Belka-DX I/Q out, you’d better believe I’ll be sampling spectrum as I travel the globe post-pandemic!

I didn’t have time to gather what I needed for making Belka-DX spectrum recordings on this trip, but you can be certain I will when I return!

I should add that one of the little joys about my dockside DXing spot this past week was watching dolphins swim by as I tuned to some of my favorite broadcasters. Bliss.

Post readers: Have you taken your radios on vacation recently? Please comment! Better yet, consider submitting a guest post with photos!

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Review Notes: Xiegu GSOC Firmware updated to version 1.1–still a number of issues

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For those of you who have been asking about the new Xiegu GSOC controller, I just updated my unit with the latest firmware (version 1.1).

Firmware notes show that it addresses the following items:

Xiegu GSOC FW V1.1
1. Solved the CW sidetone delay problem
2. Solved the problem of unstable system and occasional crash
3. Added RTTY modem
4. Added CW decoder
5. Added SWR scanner
6. Added FFT/Waterfall level adjustment
7. Added FFT line/fill color mixer

The list above was copied directly from the version notes.

I’m currently evaluating the GSOC/G90 pair which were kindly sent to me on loan by Radioddity. I upgraded the GSOC firmware to v1.1 this weekend.

What follows are some of my evaluation notes an observations after performing the upgrade.

Updating firmware

Updating the GSOC firmware is a pretty straight-forward process.

First you must download the GSOC firmware package (about 330 MB!) which includes a disk image and application to flash the image to a MicroSD card.

Yes, you’ll need a dedicated MicroSD card to upgrade the GSOC firmware–meaning, you can’t simply use a MicroSD card with data on it you’d like to keep because the process of flashing the ISO file also includes a full format with multiple partitions.

You’ll also need an SD Card reader/writer if your Windows PC doesn’t include one.

The included firmware application/tool makes it quite easy to flash a disk image on the MicroSD card.

After the MicroSD card has been prepared, simply turn off the GSOC, insert the MicroSD card on the left side of the GSOC, turn it back on and the GSOC will automatically boot from the MicroSD card and install the new OS/firmware.

Once the upgrade has completed, the GSOC will turn itself off and you must remove the MicroSD card.

If you want to restore the MicroSD card to one partition, you’ll need to perform another format and shrink the volumes.

CW sidetone latency (still issues)

After performing the upgrade, I hopped on the air and tried to make a few CW contacts since I noted in the version notes that the CW sidetone latency had been addressed. So far, my evaluation has pretty much been on hold because I’m unable to use CW mode with any sense of sending accuracy.

Unfortunately, I’m still finding that there’s still a bit of sidetone latency or keyer timing interfering with my ability to correctly send words and letters.

To my ear, it sounds like there’s much less latency in the sidetone audio now (compared with v1.0 which was a little insane) but I still struggle sending characters that end in a string of dits or dashes. For example, when I try to send a “D” the radio will often produce a “B” by adding one extra dit. Or if I try to send a “W” it might produce a “J”. I know something is a little bit off because I botched up two CW contacts with POTA stations yesterday as I tried to send my own callsign correctly.  And “73” was even problematic.

I’m guessing that there may still be a bit of audio lag between the G90 body (where the CW key is plugged in) and the GSOC (where the sidetone audio comes out). At the end of the day, the keying information must be sent to the GSOC from the G90 transceiver body and I assume the processor on the G90 is causing a bit of audio latency. Hopefully, Xiegu can sort this out. It’s a serious issue for anyone who wants to operate CW with the GSOC.

If you own the GSOC and operate CW, I’d love your comments and feedback.

Other updates

I tried using the CW decoder yesterday via the “Modem” menu and had limited success decoding a CW rag chew.

My markup in red: You can see at the very end of this conversation, it decoded the call sign, but interpreted “TU” as “TEA”

The decoder seemed to adjust the WPM rate automatically at one point, but as you can see in the image above, almost every dit was interpreted as an “E” and every dash a “T”. I must assume I don’t have it configured properly, but I don’t have an operator’s manual for reference and instruction.  I’ve also tried RTTY decoding, but haven’t been successful so far–I’m pretty sure this is also because I haven’t configured it properly.

SWR Scanner

I tested the new SWR scanner and it seems to work quite well, plotting SWR across a given frequency range. I did note, however, that it doesn’t seem to confine itself to the ham bands at all. It does inject a signal as it scans (I read 1.5 to 2 watts on my CN-801 meter).

I discovered out-of-band scanning when I took the photo above while trying to do a scan of the 30 meter band. It started around 9.6 MHz–well into the 31M broadcast band where it shouldn’t be transmitting. Xiegu needs to limit transmitted signal to the ham bands.

Memory Keying

I had hoped Voice Memory Keying would be added along with TX/RX recording. I do believe this will eventually be included in a future update. It appears via the “Modem” menu that CW Memory Keying has been added, but I can’t sort out how to make it work (again, a operation manual would be quite handy).

Audio recording

I had hoped transmit and received audio recording would be added in this firmware update; I understand this will eventually be added.

Combined current drain

As I mentioned in a previous GSOC update, the GSOC controller and G90 transceiver both need a 12V power source–indeed, each has a dedicated power port. The GSOC does not derive power from the G90.

I was originally told that the G90 and GSOC both pull about .60 amps in receive which would total 1.2 amps combined. My Hardened Power Systems QRP Ranger battery pack displays voltage and current; it’s not a lab-grade measurement device, but it’s pretty accurate. When I operate the GSOC and G90 at a moderate volume levels in receive, it appears to draw 0.95 to 0.97 amps–basically, 1 amp.

At home on a power supply, this is inconsequential, but in the field you’d need to keep this in mind when choosing a battery. It’s on par with a number of 100 watt transceivers.

Spectrum display images

I’m still finding images on the GSOC display that are not present in the received audio. I mentioned this in my initial overview and it doesn’t seem the firmware update addressed this.

I can only assume the spectrum imaging might be due to the I/Q input being too “hot” coming from the G90 via the shielded audio patchcord. Perhaps there’s a function to manually lower the I/Q gain, but I haven’t found that yet.

Spectrum images are most noticeable on the 31 meter band, but found them on the 20 meter ham band as well.

Here are two screen shots that show how images appear when a nearby signal overwhelms the GSOC:

Images are not present all of the time, only when a strong signal intrudes.

Ever-present noise and spurs in portions of spectrum

Perhaps this is related to the issue above, but there are some spurs on the spectrum display that seem to be present whether the G90/GSOC is hooked up to an antenna or dummy load.

Here’s a photo of the GSOC hooked up to an antenna:

And to a dummy load:

I’ve highlighted the spurs in red and as you can see, the intensity is stronger without an antenna thus I’m guessing this is internally-generated. The spurs do not move on the display as you change frequency.

Other notes

Again, I feel like the GSOC firmware isn’t mature and I can’t yet recommend purchasing it. I feel like Xiegu have rushed this unit to market.

I know that, over time, more features will be added and Xiegu certainly has a track record of following up.

When I evaluate a product, I keep a list of notes that I send to the manufacturer and to keep for my own reference. In Alpha and/or Beta testing, I’d share this info only with the manufacturer. Since the GSOC is a product that’s in production and widely available, however, I thought I’d share them here publicly:

  • GSOC volume control scale is 0 to 28. The difference between 0 (muted) to 1 seems to be the biggest increment. Volume 1 is actually a low to moderate volume level (i.e. a bit high).
  • Boot up time for the GSOC is 30 seconds
  • A keyboard and mouse or capacitive stylus are almost required for accurate operation. Many of the touch screen buttons are quite small and difficult to accurately engage with fingertip. The pointer seems to fall slightly below where fingertip makes contact on the screen.
  • Notch Filter seems to have no effect even after the v1.1 upgrade. There is no Auto Notch feature either.
  • I can’t seem to engage split operation even though there are A/B switchable VFOs and a “Split” button above the spectrum display. Using a keyboard and mouse doesn’t engage it either.
  • There are a number of announced features that I haven’t discovered including some WiFi and Bluetooth wireless functionality.
  • For field use, you must pack quite a bit of kit: the transceiver, the controller, CW key cable, microphone, serial cable, I/Q cable, G90 Power cable, and GSOC power cable. It would also be advisable to take a wireless keyboard and mouse especially if you plan to use any advanced functions like CW memory keying.
  • It doesn’t appear that you have CAT control of the GSOC which complicates digital operation. I believe many of us hoped the GSOC would make digital mode operation easier with the G90, but it hasn’t. Indeed, I assumed the GSOC would have an internal sound card for digi modes much like the Icom IC-7300 and IC-705. Use of VOX control is still  the best way to control transmit. I hope this can be upgraded else this would be a missed opportunity.
  • Since the v1.1 upgrade, the GSOC hasn’t crashed (it did frequently with the v1.0 firmware).
  • Not a pro or con, but I wish the AF Gain/Squelch was AF Gain/RF Gain like most HF transceivers. I’ve accidently engaged squelch twice which essentially muted audio. Pressing and holding the PO (Power Output) button opens the RG Gain control function).

The GSOC Universal Controller is an interesting accessory for the G90 and I’ve read comments from users that love the interface and added functionality.

If I’m being honest, I feel like I’m Beta testing the GSOC. I’ve yet to find a GSOC operation manual–this makes it very difficult to know if one has correctly configured the controller and engaged features/functions correctly. A quick start guide is included with the product, but it really only helps with connections and starting up the GSOC the first time. If you’re a GSOC early adopter, just be aware of this. Again, I’m pretty confident Xiegu will make refinements and include promised features in future firmware updates. I understand their software engineer closely monitors the GSOC discussion group as well. If you’re considering the purchase of a GSOC, I’d encourage you to join the GSOC group.

Questions? Comments?

As I said, I can’t recommend purchasing the GSOC controller yet. So much can change with firmware updates, however, I would encourage you to bookmark the tag GSOC to follow our updates here on the SWLing Post. I will update the GSOC controller each time a new firmware version is issued and until Radioddity asks for the loaner units to be returned. Again, many thanks to Radioddity for making this GSOC and G90 evaluation possible.

Feel free to comment with any questions you might have and I’ll do my best to answer them!

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Matt’s Monster Mediumwave Radio Selectivity Shootout!

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Many thanks to SWLing Post contributor, Matt Blaze (WB2SRI), for sharing another brilliant audio comparison featuring benchmark portable radios:

Medium wave selectivity shootout

by Matt Blaze

I did another monster medium wave portable receiver comparison, this time with the aim of comparing receivers’ ability to deal with weak signals in the presence of strong adjacent channels.

Once again, I went up to the roof with eight MW portables with built-in antennas and recorded them simultaneously along with my “reference signal”, from an Icom R-9500 with an active loop on the roof. As before, I recorded a narrated stereo mix with the Icom on the left and the rotation of radios for a minute or two each on the right, but have “solo” tracks available for the full time for each radio. The nine receivers in the lineup this time included:

  • Icom R-9500 (with amplified Wellbrook loop antenna on roof)
  • Potomac Instruments FIM-41 Field Intensity Meter (my personal favorite)
  • Panasonic RF-2200
  • Sony IC-EX5MK2
  • C.Crane Radio 2E
  • Sangean PR-D4W
  • Sangean ATS-909X
  • Tecsun PL-990X
  • XHDATA D-808

I recorded two signals, one at night and one during the day.

Nighttime Signals

The first was at night: WWL New Orleans on 870 KHz. This signal is usually weak to medium strength here, but is a challenge for two reasons: first, it shares the frequency with Cuba’s Radio Reloj, and it is squeezed between two much higher strength signals: Toronto’s CJBC on 860, and NYC’s WCBS on 880. So you need a decent receiver and careful antenna orientation to receive it well here. That said, everything did pretty well, though you can see that some radios did better than others.

The mix

Solo tracks

Icom IC-R9500

Potomac Instruments FIM-41 Field Intensity Meter

Panasonic RF-2200

Sony IC-EX5MK2

C.Crane Radio 2E

Sangean PR-D4W

Sangean ATS-909X

Tecsun PL-990X

XHDATA D-808

Daytime Signals

The second signal was during the day and was MUCH more marginal: WRJR Claremont, VA on 670 KHz. This was real challenge for any receiver and antenna. The signal was weak, and overshadowed by WCBM Baltimore on 680, a 50KW daytimer that is very strong here. (I’m not 100% sure that we were actually listening to WRJR – I never got an ID, but the station format and signal bearing was right). We can really hear some differences between the radios here.

The mix

Solo tracks

Icom IC-R9500

Potomac Instruments FIM-41 Field Intensity Meter

Panasonic RF-2200

Sony IC-EX5MK2

C.Crane Radio 2E

Sangean PR-D4W

Sangean ATS-909X

Tecsun PL-990X

XHDATA D-808

Everything (except the Icom) was powered by batteries and used the internal MW wave antenna, oriented for best reception by ear (not just maximizing signal strength, but also nulling any interference). The loop for the Icom was similarly oriented for best intelligibility.

For audio nerds: The recording setup involved a lot of gear, but made it fairly easy to manage capturing so many inputs at once. The portable radios were all connected to a Sound Devices 788T recorder, with levels controlled by a CL-9 linear mixing board control surface. This both recorded the solo tracks for the portables as well as providing a rotating mix signal for each receiver that was sent to the next recorder in the chain, a Sound Devices 833. The 833 received the mix audio from the 788T, which went directly to the right channel. The left channel on the 833 got audio from a Lectrosonics 822 digital wireless receiver, which had the feed from the Icom R-9500 in the shack (via a Lectrosonics DBu transmitter). The center channel on the 833 for narration of the mix, which I did with a Coles 4104B noise-canceling ribbon mic. This let me record fairly clean audio in spite of a fairly noisy environment with some wind.

All the radio tracks were recorded directly off the radios’ audio line outputs, or, if no line out was available, from the speaker/headphone jack through a “direct box” interface. I tried to make the levels as close to equal as I could, but varied band conditions and different receiver AGC characteristics made it difficult to be completely consistent.

Making the recordings was pretty easy once it was set up, but it did involve a turning a lot of knobs and moving faders in real time. I must have looked like some kind of mad scientist DJ to my neighbors, some of whom looked at me oddly from their own roofs.

Happy Thanksgiving weekend!

Thank you, Matt, for another brilliant audio comparison! I appreciate the attention and care you put into setting up and performing these comparisons–not an easy task to say the least. That Potomac Instruments FIM-41 is an impressive machine!

By the way, I consider it a badge of honor when the neighbors look at me as if I’m a mad scientist. I’m willing to bet this wasn’t your first time! 🙂

Post readers: If you like this audio comparison, please check out Matt’s previous posts as well:

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